The subject application relates to document printing, and more particularly to adjusting the speed and/or acceleration of a fuser drive during a print job to mitigate temperature droop during fuser operation.
In typical electrophotographic image forming devices, such as copy machines and laser beam printers, a photoconductive insulating member is charged to a uniform potential and thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in exposed or background areas and creates an electrostatic latent image on the member, which corresponds to the image areas contained within the document. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with a marking material. Generally, the marking material comprises pigmented toner particles adhering triboelectrically to carrier granules, which is often referred to simply as toner. The developed image is subsequently transferred to the print medium, such as a sheet of paper. The fusing of the toner image onto paper is generally accomplished by applying heat and pressure. A typical fuser apparatus includes a fuser roll and a pressure roll which define a nip therebetween. The side of the paper having the toner image typically faces the fuser roll, which is often supplied with a heat source, such as a resistance heater, at the core thereof. The combination of heat from the fuser roll and pressure between the fuser roll and the pressure roll fuses the toner image to the paper, and once the fused toner cools, the image is permanently fixed to the paper.
Conventional fusers suffer from initial temperature transients (droop) at the beginning of a job. This results in gloss and color variation within a job. For example, a number of sheets, typically a first and second sheet or so, come out with higher gloss, while a subsequent several sheets (e.g., 3rd to 50th sheets or so) exhibit reduced gloss relative to sheets thereafter due to the temperature transients. This problem is more pronounced in entry production and production market segments, where multiple copies of same set of images are printed on heavy weight media and highly consistent image quality is required.
In the case of constant speed operation in conventional systems, a thermal load applied to the fuser roll has the characteristics of a step-function, and a fuser control system is not able to compensate the load in a timely manner.
Accordingly, there is an unmet need for systems and/or methods that facilitate overcoming the aforementioned deficiencies.